Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

Award type：Award from international society, conference, symposium, etc.  Country：Italy

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/15389588.2024.2321915

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/15389588.2023.2278419

Language：English  

DOI： 10.1016/j.aap.2022.106793

Web of Science

Scopus

PubMed

Language：English   Publisher：Society of Automotive Engineers of Japan, INC  

Understanding car driver responses in emergency car-to-cyclist collisions is useful for developing active safety systems to reduce injuries in car-to-cyclist collisions. In this study, driver responses toward cyclists intruding into a car’s path at an intersection were investigated in scenarios with different time-to-collisions (TTC) (1.5 s and 0.8 s for the near side approach, and 2.0 s for the far side approach) using a driving simulator. The drivers’ responses to avoid collisions were braking and swerving, whereas swerving alone was not effective for avoiding collisions. Collisions occurred when the sum of braking reaction time (BRT) and car braking deceleration time was larger than the TTC when the cyclist was visible to drivers. The mean of BRT was 0.65 and 1.35 s in the near-side and far-side scenarios, respectively. The driver’s initial gaze has an important role in affecting the driver’s time to notice the cyclist. The gaze of many drivers was located on the future path (car lane) when the cyclist was visible. As the angle between the gaze direction and the cyclist was larger, the time taken for the driver to notice the cyclist was longer. As this notice time increased, the driver’s response changed consistently from swerving to braking. Through this study, a collision area is proposed using TTC and car velocity based on the collision occurrence equation.

DOI： 10.20485/jsaeijae.13.2_89

Scopus

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Crashworthiness  

In momentum-based impact models used in accident reconstructions, the restitution coefficient is a key role to determine impulses and delta-V accurately in car-to-car collisions. The restitution coefficients can be defined as the normal and the tangential direction in the contact plane, and the same value of the normal and tangential coefficients is employed in a two-dimensional PC-Crash model. Ishikawa (1993) proposed an impact model with the normal and tangential restitution coefficient, however, to the best of the author's knowledge, few studies have further investigated tangential restitution coefficients in detail. In this study, the normal and tangential restitution coefficients of the impact model were investigated based on the finite element (FE) analysis. FE simulations of angled barrier crashes with varying barrier angles as well as 16 car-to-car collisions were conducted. As the contact plane slides, the ratio of the tangential impulse to the normal impulse becomes the same value with the maximum friction coefficient. The tangential restitution coefficient is related to whether sliding occurs on the contact plane, and can be expressed as a function of the impulse ratio. The tangential restitution coefficient decreased with increasing the impulse ratio and is positive in non-sliding collisions and negative in sliding collisions. An approximate expression for the tangential restitution coefficient was formulated as a function of the generalized impulse ratio. The calculated impulses of the impact model with normal and tangential restitution coefficients were closer to the FE analysis than the PC-Crash model which uses a constant restitution coefficient of 0.1.

DOI： 10.1080/13588265.2021.1926825

Scopus

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Event date： 2022.11

Language：Chinese  

Venue：Dresden, Germany   Country：Germany  

Event date： 2022.10

Language：Japanese   Presentation type：Poster presentation  

Event date： 2020.11

Language：Japanese  

Venue：オンライン  

Event date： 2019.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Italy, Florence   Country：Italy  

Event date： 2019.6

Language：Japanese   Presentation type：Oral presentation (general)